Bananas have been referred to as “the world’s most popular fruit,” and “the world’s most popular tropical fruit”. The most commonly sold banana worldwide is the Dwarf Cavendish. The name does not refer to the size of the fruit, but to the height of the plant (pseudostem) the bananas grow on. The reason for its commercial success is its long shelf life.

Bananas ripen naturally for as long as they stay on the plant. They transition through 7 stages as they ripen

Stage 1 – All green: Freshly picked bananas.

Stage 2 - Green with a trace of yellow: Initial stage of the ripening process, however there is still some time before they are ready to eat.

Stage 3 - More green than yellow: As the skin changes colour, the starches inside turn to sugars. This is the earliest stage that most retailers will sell bananas at.

Stage 4 - More yellow than green: A creamy texture starts developing and the natural sugar content rises. This is the most ideal stage to sell bananas at.

Stage 5 - Yellow with a trace of green: Ideal stage to eat bananas. The fruit is sweet, creamy and firm on the inside. Most retailers will sell bananas at this stage.

Stage 6 - All yellow: At the peak of freshness now, and delicious to eat. The fruit is also starting to soften as it ages and is heading towards its top sugar content. This is the latest stage most retailers will sell bananas at.

Stage 7 - Yellow with brown speckles: At the final stage of banana ripening, the skin develops black or brown sugar spots and the inside reaches its sugar peak and goes mushy.

 

Once they are picked bananas will not ripen further, unless sprayed with ethylene gas. Exposure to the gas will restart the ripening process, until the bananas themself start producing it, which sees the process to the end.  

Ethylene is also released from apples as they ripen.

banana ripening
Credit: Soltani M, Alimardani R, Omid M. Journal of Food Engineering 2011:105(4);625–631.